Embodiments of the present invention as exemplarily described herein relate generally to apparatuses for handling fluids within a chamber and to methods of handling fluids within a chamber. More particularly, embodiments of the present invention relate to apparatuses and methods capable of effectively delivering a carrier gas over a target disposed within a chamber and for efficiently purging a chamber of a fluid.
Analysis systems, such as mass spectrometry (MS) systems, optical emission spectrometry (OES) systems and the like, can be used to analyze the composition of a target (e.g., a solid target material). Often, a sample of the target is provided to an analysis system in the form of an aerosol. As is known in the art, an aerosol generally characterized as a colloid suspension of solid and possibly liquid particles in a carrier gas such as helium (He). The aerosol is typically produced by arranging the target in a sample chamber, introducing a flow of a carrier gas within the sample chamber, and ejecting a portion of the target (e.g., by ablating a portion of the target with laser light), in the form of particles. Thereafter, the ejected particles are typically entrained by the flowing carrier gas and transported to an analysis system via a sample transport conduit.
Generally, the sample chamber includes an access opening that permits passage of the target into and out of the sample chamber. However, if the sample chamber is located in an environment containing atmospheric gases (e.g., oxygen, nitrogen, carbon dioxide, etc.) the atmospheric gases can invade the interior of the sample chamber whenever the target passes through the access opening. Atmospheric gases within the sample chamber can mix with the flowing carrier gas and be delivered to the analysis system with the sample. As a result, the quality of the analysis performed by the analysis system can be degraded due to the presence of the atmospheric gases with the sample. The presence of atmospheric gases such as oxygen and nitrogen in the sample chamber can also cause formation of interfering species that are ultimately transported to the analysis system, which can also degrade the quality of the analysis performed by the analysis system. The presence of atmospheric gases within the sample chamber is also problematic because a varied or inhomogenous distribution of gases within the sample chamber can cause a different analytical response to samples generated from different areas of the target, ultimately leading to poor positional reproducibility of the analytical technique. Therefore, a user will get a different analytical result from the same target depending upon where the sample of the target was obtained.
Conventionally, atmospheric gases are removed from the interior of the sample chamber via a sample transport conduit. However, the inlet of the of the sample transport conduit is typically arranged within a middle or upper portion of the sample chamber at a location selected for optimal collection of the aerosol generated from the target—not for purging atmospheric gases, which can be heavier than, or more dense than, the carrier gas. Therefore conventional atmospheric gas removal techniques which involve the use of the aerosol transport conduit are inefficient, resulting in lengthy purge times and often a residual amount of atmospheric gases within the sample chamber.
Another conventional technique involves the use of a vacuum pump to suck out atmospheric gases from the interior of the sample chamber. In cases where the sample chamber is a laser ablation chamber including a transmission window (typically formed of quartz), a high vacuum generated by the vacuum pump may undesirably crack the transmission window. Therefore, the ability to quickly evacuate atmospheric gases from the laser ablation chamber using the vacuum pump can be significantly impaired.